scholarly journals Effect of Inclusions on the Corrosion Properties of the Nickel-Based Alloys 718 and EP718

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1177 ◽  
Author(s):  
Ekaterina Alekseeva ◽  
Andrey Karasev ◽  
Pär G. Jönsson ◽  
Aleksey Alkhimenko
Keyword(s):  
Corrosion Resistance ◽  
Alloy 718 ◽  
Corrosion Properties ◽  
Electrolytic Extraction ◽  
Operational Conditions ◽  
Large Size ◽  
Size Number ◽  
Resistance To Deformation ◽  
The Given ◽  
Harmful Effects

Inclusions in steels and alloys are known to lower the resistance to deformation, as well as to lower the mechanical, corrosion and other properties. Studies of inclusions in nickel-based alloys are important since these materials could suffer from corrosion degradation in harsh operational conditions. This, in fact, could lead to a pitting initiation around the inclusions. Two industrial Ni-based alloys (alloy 718 and EP718) were investigated to determine the harmful effects of different inclusions on the corrosion resistance of Ni-based alloys. Specifically, the inclusion characteristics (such as composition, morphology, size, number and location) were determined for inclusions collected on film filters after electrolytic extraction and dissolution of a metal matrix around different inclusions on surfaces of metal samples after electrolytic extraction (EE). It was found that both Ni-based alloys contain various inclusion types: carbides (large size NbTi-C and small multicomponent carbides), nitrides TiNb-N and sulphides (TiNb-S in EP718 alloy). The most harmful effects on the corrosion resistance of metal were detected around sulphides and small carbides containing Mo, W, Cr. Dissolution effects were also observed around large carbides and nitrides, especially around inclusions larger than 10 µm. Moreover, the dissolution of a matrix around inclusions and clusters located on the grain boundaries were found to be 2.1–2.7 times larger compared to inclusions found inside of grains of the given alloy samples.

scholarly journals Effect of Inclusions on the Corrosion Properties of Nickel Based Alloys 718 and EP718

2020 ◽  
Author(s):  
Ekaterina Alekseeva ◽  
Andrey Karasev ◽  
Pär G. Jönsson ◽  
Aleksey Alkhimenko
Keyword(s):  
Corrosion Resistance ◽  
Metal Matrix ◽  
Harmful Effect ◽  
Corrosion Properties ◽  
Electrolytic Extraction ◽  
Operational Conditions ◽  
Large Size ◽  
Size Number ◽  
Two Samples ◽  
The Given

Inclusions in steels and alloys are known as factors that could lower deformation, mechanical, corrosion and other properties. Study of inclusions in nickel based alloys is important since these materials could suffer from corrosion degradation in harsh operational conditions, where inclusions could lead to a pitting initiation. For estimation of a harmful effect of different inclusions on corrosion resistance of Ni-based alloys, inclusion characteristics (such as composition, morphology, size, number and location) on film filter and dissolution of metal matrix around different inclusions on surfaces of metal samples after electrolytic extraction (EE) were investigated in two samples of industrial Ni-based alloys (alloy 718 and EP718). It was found that both Ni-based alloys have various inclusions: carbides (large size NbTi-C and small multicomponent carbides), nitrides TiNb-N and sulfides (TiNb-S in EP718 alloy). The higher harmful effect on corrosion resistance of metal was detected around sulfides and small carbides containing Mo, W, Cr. Dissolution effect was also observed around large carbides and nitrides, especially around inclusions having size more than 10 µm. Moreover, the dissolution of metal matrix around inclusions and clusters located on the grain boundaries is 2.1-2.7 times larger compared to that for those inclusions inside of grains of the given alloy samples.

scholarly journals Characterization of non-metallic inclusions in corrosion -resistance nickel - based EP718 and 718 alloys by using electrolytic extraction method

2019 ◽  
Vol 121 ◽  
pp. 04004 ◽  
Author(s):  
Andrey Karasev ◽  
Ekaterina Alekseeva ◽  
Aleksey Lukianov ◽  
Pär G. Jönsson
Keyword(s):  
Corrosion Resistance ◽  
Extraction Method ◽  
Oil And Gas ◽  
Three Dimensional ◽  
Steel Production ◽  
Immersion Test ◽  
Corrosion Properties ◽  
Electrolytic Extraction ◽  
Electrochemical Tests ◽  
Metallic Inclusions

It is known that non-metallic inclusions (NMI) that are formed during steel production and heat treatment can significantly affect the properties of final steel products. Therefore, it is very important to be able to determine the content of harmful NMI in steels. Nickel-based alloys are widely used in the oil and gas recovery industry, due to a good combination of strength and corrosion properties. Earlier studies have shown that the corrosion properties in immersion test and electrochemical tests for Ni-based EP718 alloys are slightly lower than that for 718 alloys. The focus in this study was the influence of different NMI on the corrosion resistance of these alloys. The characteristics of inclusions (such as size, morphology, and chemical composition) were analysed by using the electrolytic extraction method followed by three-dimensional investigations using SEM in combination with EDS. It was found that some non-metallic inclusions in EP718 alloys significantly reduce its corrosion resistance. It was also shown that a primary dissolution of the metal matrix occurs around certain inclusions during electrolytic extraction. Based on obtained results, the corrosion active non-metallic inclusions can be determined in these Nickel-base alloys and some recommendations for optimization of their production technology can be formulated.

scholarly journals Electrodeposition of Copper and Brass Coatings with Olive-Like Structure

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1762
Author(s):  
Artur Maciej ◽  
Natalia Łatanik ◽  
Maciej Sowa ◽  
Izabela Matuła ◽  
Wojciech Simka
Keyword(s):  
Corrosion Resistance ◽  
Cathodic Current Density ◽  
Bath Composition ◽  
Cathodic Current ◽  
Corrosion Properties ◽  
Fine Grained ◽  
Electrodeposited Coating ◽  
Copper Zinc ◽  
New Generation ◽  
First Time

One method of creating a brass coating is through electrodeposition, which is most often completed in cyanide galvanic baths. Due to their toxicity, many investigations focused on the development of more environmentally friendly alternatives. The purpose of the study was to explore a new generation of non-aqueous cyanide-free baths based on 1-ethyl-3-methylimidazolium acetate ionic liquids. The study involved the formation of copper, zinc, and brass coatings. The influence of the bath composition, cathodic current density, and temperature was determined. The obtained coatings were characterized in terms of their morphology, chemical composition, phase composition, roughness, and corrosion resistance. It was found that the structure of the obtained coatings is strongly dependent on the process parameters. The three main structure types observed were as follows: fine-grained, porous, and olive-like. To the best knowledge of the authors, it is the first time the olive-like structure was observed in the case of an electrodeposited coating. The Cu-Zn coatings consisted of 19–96 at. % copper and exhibited relatively good corrosion resistance. A significant improvement of corrosion properties was found in the case of copper and brass coatings with the olive-like structure.

scholarly journals Influence of Rust Inhibitor on the Corrosion Resistance of Reinforcement in Cement Paste with Chloride

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 606
Author(s):  
Linchun Zhang ◽  
Ailian Zhang ◽  
Ke Li ◽  
Qian Wang ◽  
Junzhe Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Cement Paste ◽  
Photoelectron Spectroscopy ◽  
Electrical Resistance ◽  
Corrosion Properties ◽  
Passivation Film ◽  
Steel Bars ◽  
Assembly Unit ◽  
Chloride Environment ◽  
Rust Inhibitor

The electrical resistance and polarization effect of cement paste containing reinforcement were tested to research the anti-corrosion properties of steel bars in cement paste. Moreover, the microstructure and composition of passivation film and rust on the steel bars were studied. The water–cement ratio of the cement paste in this study was 0.3, with 0.5% NaCl, 1% NaNO2, and 1% Benzotriazole, and an assembly unit of 0.5% NaNO2 + 0.5% Benzotriazole by mass of cement was added to the cement to provide a chloride environment. X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were applied to research the composition of the passivation film and the microstructure of the cement paste, respectively. The results indicated that the samples with the assembly unit of 0.5% NaNO2 + 0.5% Benzotriazole showed the highest electrical resistance and polarization electrical resistance, while the specimens with 1.0% Benzotriazole showed the lowest electrical resistance and polarization electrical resistance. Moreover, the passivation film of steel bars weakened with increasing distance from the surface of the steel bars. Therefore, the corrosion of steel bars becomes more serious with increasing distance. Finally, the influence of the rust inhibitor on the corrosion resistance of steel bars in the specimens decreased in the following order: 0.5% NaNO2 + 0.5% Benzotriazole >1.0% NaNO2>1.0% Benzotriazole.

scholarly journals Development of Al–Mg–Si alloy performance by addition of grain refiner Al–5Ti–1B alloy

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110294
Author(s):  
Khaled Abd El-Aziz ◽  
Emad M Ahmed ◽  
Abdulaziz H Alghtani ◽  
Bassem F Felemban ◽  
Hafiz T Ali ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Corrosion Resistance ◽  
Testing Machine ◽  
Dendritic Structure ◽  
Grain Refiner ◽  
Corrosion Properties ◽  
Average Grain Size ◽  
Structural Applications ◽  
Alloy Addition

Aluminum alloys are the most essential part of all shaped castings manufactured, mainly in the automotive, food industry, and structural applications. There is little consensus as to the precise relationship between grain size after grain refinement and corrosion resistance; conflicting conclusions have been published showing that reduced grain size can decrease or increase corrosion resistance. The effect of Al–5Ti–1B grain refiner (GR alloy) with different percentages on the mechanical properties and corrosion behavior of Aluminum-magnesium-silicon alloy (Al–Mg–Si) was studied. The average grain size is determined according to the E112ASTM standard. The compressive test specimens were made as per ASTM: E8/E8M-16 standard to get their compressive properties. The bulk hardness using Vickers hardness testing machine at a load of 50 g. Electrochemical corrosion tests were carried out in 3.5 % NaCl solution using Autolab Potentiostat/Galvanostat (PGSTAT 30).The grain size of the Al–Mg–Si alloy was reduced from 82 to 46 µm by the addition of GR alloy. The morphology of α-Al dendrites changes from coarse dendritic structure to fine equiaxed grains due to the addition of GR alloy and segregation of Ti, which controls the growth of primary α-Al. In addition, the mechanical properties of the Al–Mg–Si alloy were improved by GR alloy addition. GR alloy addition to Al–Mg–Si alloy produced fine-grained structure and better hardness and compressive strength. The addition of GR alloy did not reveal any marked improvements in the corrosion properties of Al–Mg–Si alloy.

The Corrosion Resistance of Hard Anodised EN AW 7075 T6 Alloy

2021 ◽  
Vol 105 (1) ◽  
pp. 329-337
Author(s):  
David Kusmič ◽  
Lenka Klakurková ◽  
Martin Julis ◽  
Pavel Gejdoš ◽  
Jindrich Vilis ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Bulk Material ◽  
Surface Hardness ◽  
Hot Water ◽  
Initial Surface ◽  
Corrosion Properties ◽  
Resistance Surface ◽  
Hard Anodizing ◽  
Deaerated Solution ◽  
7075 Alloy

In this paper, commercially cold-rolled and artificial aged EN AW 7075 T6 alloy has been used. To ensure increased corrosion resistance, surface hardness, scratching resistance, and aesthetic features, this aluminium alloy was subsequently hard anodised and hot-water sealed (AC-A). The hard anodizing and sealing process increased surface hardness up to 304±13 HV 1 from an initial surface hardness of 194±3 HV 1. Also, the microhardness of the anodised layer and bulk material has been documented. Scanning electron microscopy (SEM) was used for microstructure and trapped precipitates investigation in the 42.9±1.4 thick formed anodised layer investigation. The T6 treated (AC) and hard anodised together with sealed (AC-A) EN AW 7075 alloy corrosion properties were evaluated using the anodic potentiodynamic polarisation tests (PPT) in a neutral 2.5% NaCl deaerated solution. The corrosion rate CR (mm/y) decreased approx. 39-times for the hard anodised and sealed EN AW 7075 alloy (AC-A), associated with the shift of the Ecorr (mV) to more positive values, degreased Icorr (µA) and increased Rp (Ohm) values compared to the artificial aged (AC) alloy. Additionally, the pitting was evaluated using laser confocal microscopy, and the pitting coefficient was also calculated.

scholarly journals Study of Molten Salt Corrosion of Superni-75 using Termogravimetric Technique

1970 ◽  
Vol 3 (2) ◽  
pp. 77-82 ◽  
Author(s):  
TS Sidhu ◽  
S Prakash ◽  
RD Agrawal
Keyword(s):  
Corrosion Resistance ◽  
Molten Salt ◽  
Hot Corrosion ◽  
Corrosion Behaviour ◽  
Thick Layer ◽  
X Ray Diffraction ◽  
Salt Corrosion ◽  
Marine Engineering ◽  
The Given ◽  
Kinetics Of

The present study aims to evaluate the hot corrosion behaviour of the Ni-based alloy Superni- 75 in the molten salt environment of Na2SO-60%V2O5 at 900°C under cyclic conditions. The thermogravimetric technique was used to establish the kinetics of corrosion. X-ray diffraction, scanning electron microscopy/energy-dispersive analysis and electron probe microanalysis techniques were used to analyse the corrosion products. Superni-75 has successfully provided the hot corrosion resistance to the given molten salt environment. The hot corrosion resistance of the Superni-75 has been attributed to the formation of uniform, homogeneous and adherent thick layer of the scale consisting mainly of oxides of nickel and chromium, and refractory Ni(VO3)2. These oxides and refractory nickel vanadates have blocked the penetration of oxygen and other corrosive species to the substrate. Keywords: Hot corrosion, nickel-based alloy, superalloy, molten salt environment   DOI: 10.3329/jname.v3i2.922 Journal of Naval Architecture and Marine Engineering 3(2006) 77-82

Corrosion behavior of new type Co-based superalloys with different Ni contents

2017 ◽  
Vol 35 (6) ◽  
pp. 455-462 ◽  
Author(s):  
Bo Gao ◽  
Lei Wang ◽  
Yang Liu ◽  
Xiu Song ◽  
Shu-Yu Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Hot Corrosion ◽  
Corrosion Layer ◽  
Corrosion Process ◽  
Corrosion Properties ◽  
Oxidation Processes ◽  
Ni Content ◽  
Ni Addition ◽  
New Type

AbstractThe corrosion properties of γ′-strengthened Co-xNi-Al-W-Cr (where x=15, 20, 25, and 30 at.%) superalloys were investigated in the mixture of 75 wt.% Na2SO4+25 wt.% NaCl at 900°C. The results showed that the corrosion behavior is associated with both sulfuration and oxidation processes. It was demonstrated that increasing the addition of Ni effectively promoted the formation of continuous Al2O3 scales, so that the hot corrosion resistance could be improved. When Ni content is more than 20 at.%, a large amount of Ni3S2 precipitates during the corrosion process. Sulfuration can destroy the integrity of the corrosion layer and increase the activity of oxygen. In this way, the internal oxidation of the alloys becomes more serious. Therefore, it is recommended that the optimum Ni addition is about 20 at.% for new type Co-Ni-Al-W-Cr superalloys.

scholarly journals Effect of Plasma Nitriding Process Conditions on Corrosion Resistance of 440B Martensitic Stainless Steel

2014 ◽  
Vol 8 (3) ◽  
pp. 156-159 ◽  
Author(s):  
Magdalena Łępicka ◽  
Małgorzata Grądzka-Dahlke
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Degradation Products ◽  
Plasma Nitriding ◽  
Electrochemical Corrosion ◽  
Industrial Applications ◽  
Process Conditions ◽  
Corrosion Properties ◽  
Dental Instruments ◽  
Increased Risk

Abstract Martensitic stainless steels are used in a large number of various industrial applications, e.g. molds for plastic injections and glass moldings, automotive components, cutting tools, surgical and dental instruments. The improvement of their tribological and corrosion properties is a problem of high interest especially in medical applications, where patient safety becomes a priority. The paper covers findings from plasma nitrided AISI 440B (PN-EN or DIN X90CrMoV18) stainless steel corrosion resistance studies. Conventionally heat treated and plasma nitrided in N2:H2 reaction gas mixture (50:50, 65:35 and 80:20, respectively) in two different temperature ranges (380 or 450°C) specimens groups were examined. Microscopic observations and electrochemical corrosion tests were performed using a variety of analytical techniques. As obtained findings show, plasma nitriding of AISI 440B stainless steel, regardless of the process temperature, results in reduction of corrosion current density. Nevertheless, applying thermo-chemical process which requires exceeding temperature of about 400°C is not recommended due to increased risk of steel sensitization to intergranular and stress corrosion. According to the results, material ion nitrided in 450°C underwent leaching corrosion processes, which led to significant disproportion in chemical composition of the corroded and corrosion-free areas. The authors suggest further research into corrosion process of plasma nitrided materials and its degradation products.

Relationships between Textures and Surface Roughness, Frictional Behavior, Erosion and Corrosion Properties of TiN Films

2004 ◽  
Vol 449-452 ◽  
pp. 781-784 ◽  
Author(s):  
Hee Dong Kim ◽  
In Soo Kim ◽  
Dong Young Sung ◽  
Min Gu Lee ◽  
S. Dost ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Corrosion Resistance ◽  
Friction Coefficient ◽  
Physical Vapor Deposition ◽  
Textured Surface ◽  
Corrosion Properties ◽  
Tin Films ◽  
Physical Vapor Deposition Method ◽  
Erosion Corrosion ◽  
Better Than

TiN coated films were prepared by a reactive ion physical vapor deposition method. In this research, we studied the relationships between textures and friction coefficient, erosion-corrosion resistance and corrosion resistance in textured TiN films. The surface roughness of (115) textured TiN films is lower than that of (111) textured TiN films. The friction coefficient of (115) textured surface is similar with that of (111) textured surface of TiN coated films. The erosion-corrosion and corrosion resistance of (115) textured surface is better than that of (111) textured surface of TiN coated films.

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